Bomb squad teams have been called out four times in the last 24 hours to deal with false alarms and at least one viable pipe bomb.
In one alert, the Israeli embassy in Ballsbridge, Dublin, was evacuated for two hours after a member of staff raised the alarm over a suspicious package.
The Defence Forces bomb disposal team inspected the parcel and declared it a false alarm.
Elsewhere, a unit was called out to a house on Cushlawn Park in the Tallaght area of the capital following a bomb scare.
The residential area was cordoned off just after 2.30am by gardai and local people were evacuated to a safe location.
A spokesman for the Defence Forces said the viable device, understood to be a pipe bomb, was found outside a house.
It was made safe and transported to a military base for further inspection, and the area was declared safe within an hour.
Later, a team was ordered back to Tallaght at 10.30am after components for an improvised explosive device were discovered in a laneway between homes.
It happened in the Raheen-Whitebrook area.
A fourth alarm was raised later in the day when a suspicious package was found on a lane in street in the Sallynoggin area.
The Defence Forces bomb disposal team have had 133 call-outs this year, dealing with pipe bombs, conventional munition destruction such as old grenades, unstable chemicals in labs, colleges and schools, and suspect devices found to be hoaxes.